Mycologia (2001) 93, 440-446

Hanna Johannesson, Mårten Gustafsson and Jan Stenlid (2001)
Local population structure of the wood decay ascomycete Daldinia loculata
Mycologia 93 (3), 440-446
Abstract: This paper presents a study of the local population structure of Daldinia loculata, a xylariaceous species frequently producing conidia and sexual stromata on fire-damaged deciduous host trees. We were able to show endophytical establishment of D. loculata by isolating mycelia from sound-looking wood of 8 out of 14 freshly felled, non-burned trees. Mycelia were isolated from all 17 burnt trees in a burned forest site of central Sweden hosting stromata of D. loculata, and the distribution of genets in the stand was determined by using both vegetative incompatibility tests and restriction enzyme analysis of PCR amplified nuclear gene fragments as codominant molecular markers. In 14' of the trees we found only one genet of D. loculata per stem, and in three of the trees we found two genets per stem. Each genet was found only once in the stand, highlighting the relative importance of ascospores instead of conidia for dispersal to new substrata. Only one allele per locus was found in the mycelium isolated from the wood, suggesting that D. loculata grows vegetatively as haploid mycelia. Vegetative incompatibility and segregating molecular markers were observed in the progeny of single stromata, evidently a consequence of D. loculata being heterothallic. More than two alleles of a highly variable multiallelic locus were detected in each of two stromata when analyzing single ascospores from 14 to 16 perithecia, evenly distributed on the stromatal surface, suggesting that more than one mating event can be involved in stroma formation in D. loculata. Moreover, most genotyped stromata of the same tree showed a distinct heterozygous genotype, indicating multiple matings of the relatively large, haploid, vegetative mycelium in the wood by several second, very small, individual mycelia.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Jan Stenlid

Research topic(s) for pests/diseases/weeds:
molecular biology - genes
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Daldinia loculata	Birch (Betula)